# Convert png to pdf in Golang

Converting a PNG (Portable Network Graphics) image to a PDF (Portable Document Format) document is a common task in the world of programming. In this article, we will explore how to convert a PNG image to a PDF document using the Go programming language.

To convert a PNG image to a PDF document, we will use the `encoding/pdf` package from the standard Go library. This package provides functions and types that allow us to create and manipulate PDF documents.

To begin, we will import the `encoding/pdf` package and the `image/png` package, which provides support for reading and writing PNG images.

```go
import (
    "image/png"
    "encoding/pdf"
)
```

Next, we will open the PNG image file using the `png.Decode` function. This function returns an `image.Image` object, which represents the PNG image in memory.

```go
// Open the PNG image file.
pngFile, err := os.Open("image.png")
if err != nil {
    // Handle the error.
    return
}
defer pngFile.Close()

// Decode the PNG image.
pngImage, err := png.Decode(pngFile)
if err != nil {
    // Handle the error.
    return
}
```

Now that we have the PNG image in memory, we can create a new PDF document and add the PNG image to it. To create a new PDF document, we will use the `pdf.New()` function, which returns a `pdf.Document` object.

To add the PNG image to the PDF document, we will first create a `pdf.Image` object using the `pdf.NewImageFromImage()` function. This function takes an `image.Image` object as an argument and returns a `pdf.Image` object that can be added to the PDF document.

Once we have a `pdf.Image` object, we can use the `pdf.AddImage()` function to add the image to the PDF document. This function takes the `pdf.Image` object and the desired width and height of the image in the PDF document as arguments.

```go
// Create a new PDF document.
pdfDocument := pdf.New()

// Create a new PDF image from the PNG image.
pdfImage := pdf.NewImageFromImage(pngImage)

// Add the image to the PDF document with a width of 500 points and a height of 400 points.
pdfDocument.AddImage(pdfImage, 500, 400)
```

Finally, we can save the PDF document to a file using the `pdf.Encode()` function. This function takes a `pdf.Document` object and an `io.Writer` object as arguments, and it writes the PDF document to the specified writer. In this case, we will use the `os.Create()` function to create a new file and use that file as the writer for the PDF document.

```go
// Save the PDF document to a file.
pdfFile, err := os.Create("image.pdf")
if err != nil {
    // Handle the error.
    return
}
defer pdfFile.Close()

// Encode the PDF document to the file.
if err := pdfDocument.Encode(pdfFile); err != nil {
    // Handle the error.
    return
}
```

With that we have successfully converted the png file to pdf format.

If you liked this article, please share it with others.